My depression is affecting my relationships. Should I seek treatment? What can I expect?

I know I am depressed because I haven't felt well in months. It is affecting the people I love and I want to seek help. I really want to be able to relate to people the way that I used to. I've lost pretty much everyone because I've had nothing to say, nothing to contribute to anyone. I know I need to be more pleasant and easier to deal with and not feeling the need to bombard people with my issues and not expecting them to cure my loneliness. My question is pretty open to any advice but one thing I do want to know is what kind of questoins to expect from a doctor. I haven't been to a doctor in over ten years and I don't know what to expect. Will they take me seriously? Will they prescribe medication? Will this medicine interfere with my already terrible ability to sleep? Will it make me more suicidal? I am really nervous...